Please Note: The main page lists projects via BBSRC Research Theme(s) quoted and then relevant Topic(s).
The Plant-Insect-Fungi Interaction: exploring the dynamic relationship between plant host, insect and entomopathogenic fungi biopesticide efficacy
Secondary Supervisor(s): Dr Tom Pope, Dr Alex Watson-Lazowski, Dr Joe Roberts
University of Registration: Harper Adams University
BBSRC Research Themes:
Project Outline
With increasing concern over the overreliance, economic cost, environmental impact and build-up of resistance towards synthetic pesticides, there has been increasing interest and uptake of biopesticides and integrated pest management (IPM) strategies within protected horticulture. One type of biopesticide, are entomopathogenic fungi (EPF), which are parasitic microorganisms with an ability to infect and kill insect pests. Advantages of using EPF are that they present no mammalian toxicity, are naturally occurring, have differing modes of action to other biopesticides and are specific to the target pest organisms (1). The array of enzymes (2) needed for successful colonisation of insects by EPF, and the complexity of the interaction between EPF genes and pathogenicity, result in insect resistance to EPF building up much slower than chemical controls, a significant advantage over chemical counterparts. However, there are currently few commercial EPF products available to UK growers; Mycotal (based on Lecanicullium muscarium) used to control whitefly by Koppert, and Naturalis-L by Fargro (based on Beauveria bassiana) also used predominantly for whitefly in UK glasshouses.
Reported disadvantages of EPF are that virulence is affected by abiotic (such as temperature, relative humidity, UV exposure etc.) and biotic factors (interaction with the host plant, target insect species and their endosymbionts, other EPF species present) (3,4). In addition, applications of EPF (for instance filtrates versus applications of conidia (2)) need to be insect specific and take into account how other IPM controls may impact effectiveness. Successful infection of EPF relies on both the EPF-insect interaction and environment. Furthermore, there is anecdotal evidence and preliminary data to suggest that the background level of essential oils within herb crops may impede the efficacy of EPF, suggesting a fascinating and dynamic plant-insect-fungi interaction that determines the efficacy of EPF as a biological pest control. Exploring this currently understudied plant-insect-fungi interaction is the basis of this project proposal.
This project will explore the interaction between collected Myzus persicae (peach-potato aphid) and EPF to determine the extent to which host plants can influence said interaction. Interaction will be measured through an assessment of the insect’s performance, feeding behaviour and gene expression, when exposed to herb crops that have differing endogenous essential oil profiles.
The project can be divided into four work packages, which a successful student will develop, adopt and refine:
Work package one (WP1) will involve connecting to British Herb Association growers using a survey to assess the agronomic practises (including varieties) that result in distinctive essential oil profiles. This may be supplemented by glasshouse experiments to test and verify grower experiences. This work will result in the student selecting the most appropriate herb crops to take forward in their research.
Work package two (WP2) will consist of a series of aphid performance assays on the chosen herbs from WP1. The aphids for this will be collected from different commercial crops, to quantify the variation across clonal populations. Aphids will be exposed to EPF through either direct contact or odour exposure. Performance can be assessed using fecundity, intrinsic rate of growth and biomass measurements.
Work package three (WP3) will establish behavioural (using Electrical Penetration Graph technique and scoring) and gene expression changes (using RNA-sequencing and the wealth of genetic resources available for M. persicae) of a subset of the selected M. persicae from WP2 when exposed to EPF on distinct herb crops chosen in WP1.
Work package four (WP4) will involve examining the interaction of M. persicae and EPF in the ways described in WP2, with the addition of chosen exogenous essential oil applications from the literature.
References
1. Khan, S., Guo, L., Maimaiti, Y., Mijit, M. and Qui, D. 2012. Entompathogenic Fungi as Microbial Biocontrol Agent. Molecular Plant Breeding 3 (2), 63-79.
2. Khan, S., Guo, L., Shi, H., Mijit, M. and Qui, D. 2012. Bioassay and enzymatic comparison of six entomopathogenis fungal isolates for virulence or toxicity against green peach aphids Myzus persicae. African Journal of Biotechnology 11 (77), 14193-14203.
3. Robles-Acosta, I. N., Chacón-Hernández, J. C., Torres-Acosta, R. I., Landeros-Flores, J., Vanoye-Eligio, V. and Arredondo-Valdés, R. 2019. Entomopathogenic fungi as biological control agents of Phyllocoptruta oleivora (Prostigmata: Eriophyidae) under greenhouse conditions. Florida Entomologist 102 (2): 303-308.
4. Mantzoukas, S., Kitsiou, F., Natsiopoulos, D. and Eliopoulos, P. A. 2022. Entomathogenic Fungi: Interactions and Applications. Encyclopedia 2; 646-656.
